Electrical protective apparatus.



no. 845,010. v QPATENTED FEB. 19, 1907.

- 0. A. ROLFE.

ELECTRICAL PROTECTIVE APPARATUS.

APPLICATION FILED FEB. 4. 1905.

ggjiese UNITED STATES PATENT OFFICE.

CHARLES A. ROLFE, OF ROCHESTER, NEW YORK, iSSieNORjTO ROLEE ELEC- TRIO CoMPAvY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

ELECTRICAL PROTECTIVE APPARATUS- Patented Feb '19, 1 907.

Original application filed April 21, 1902, Serial No. 104,02 1. Divided and this application filed February 4., 1905. Y s ntinel 244,238.

To all whom it may concern.-

Be it known that I, GHARLES 'A. ROLEE, a citizen of the United States, residing at Rochester, in the county of Monroe and State of New York, have invented a certain new and. useful Improvement in Electrical Protective Apparatus, of which the following is a full, clear, concise, and exact description, reference being had to the accom anying drawings, forming a part of this specification.

My invention relates to electrical circuit protective apparatus for protecting electrical instruments and circuits from the injurious effects of unduly-strong currents.

In an application filed by me April 21, 1902, Serial No. 104,021, Electrical-circuit protector, I have shown and described an electrical-circuit protective apparatus involving the novel form of protective device which can be used either in an individual protector or -in bank and have shown this protective device mounted in bank for use at telephone-exchanges and the like.

The present application is a division of my said other application, the latter containing the claims for the protective device, whereas the present application contains the claims for the mounting or arrangement of pr,o'

tectors, with their connecting instrumentalities, upon a switchboard or similar .bank device.

In the accompanying drawings, Figure 1 is a view, partly in elevation and partly in vertical section, of a section of electrical-circuit protective apparatus comprising a plurality of protectors and lightning-arresters mounted in accordance with the invention of my present application. Fig. 2 is a side elevation of the Same. views of certain parts of one of the protectors, Fig. 5 being a section taken on line 5 5 in Fig. 3. Fig. 6 is a view similar to Fig. 3 of a modified form of device, and Fig. 7is a section taken on line 7 7 in Fig. 6.

In the drawings I have showna section of an apparatus intended for a telephone-exchange or other place where a plurality of lines are assembled and where it is desirable to group the protectors for the various lines together. The apparatus shown comprises a supporting plate or structure 1, which is conveniently made of metal covered with insulating material, as shellac. This plate has Figs. 3, 4, and 5 are a series of protective devices'arranged on each side of 1t. In Fig.1 theend protectors of the two series appear on opposite sides of the plate, and in Fig. 2 two protectors are shown on one Sideof the plate, 1t being understood that there are any desired number in the series-and that the number of protectors in the two Series on opposite sides of theplate are desirably the same. 1

Each protector comprises a pair of springarms 2 and 3, which tend to'swing orseparate from one another. The .upper ends of each pair of spring-arms 2 and 3 support what I shall term a heat-cartridge, in this case conveniently consisting of a graphite stick 4 and.caps 5 and 6 soldered to the opposite ends of the graphitesti'ck by hardso derthat is, solder which meltsat a comparatively high temperature. i

7, as shown in Figs. 3 and' i, which permits it to be slid into a slot formedin the springarm 2. The cap 6 has its end slotted, as shown in Fig, 5, and a swinging lever .8 is ar ranged between the slotted portions and pivoted near its upper end by apivot 9. This lever 8 is constructed with an outwardly extending portion 10 at itsfupper'fend', and a spring 11 is secured to the innerend of the cap 6 and extended over the projectiorfl of the lever 8 and adapted to press downwardly upon the same, so as to tend normally to move the lever so as to s'wirigits lower end inwardly. The' lever 8 longer than the width of the cap, so that aporti'on of it projects below the same, and the spring-arm 3 Y i is slotted, as shown in Fi 2, so that the narrowed slotted portion of the cap can fit therein, while the lower'end of the lever will engage the arm at the end of the slot. The lever is soldered in position between" the forked or slotted portion of the cap 6 by layers 12 12 of Soft solderthat is, solder which will melt or soften at a comparatively low temperature. The graphite stick 4 is of such internal resistance that it will'become' sufiiciently heated by an unduly-strong current to melt or soften the layers 12 12 of soft solder, but not to melt the solder by which the caps 5 and 6 are secured to its ends. \Vhen the device iS in normal condition, the spring-arm 2 is engagedby'the cap 5 and the spring-arm 3 by the lower end of the lever 8,

whereby these spring-arms are held in resirtraint, as shown at the left-hand side of I'm-between the protectors and the support ing-plate 1 are lightning-arrester contactsprings 13 13, and on the outer sides of the protectors are locel-circuit contstct-strips14 1.4 and 15 15. Thecontact-strips 14- 1415 15 have their upper ends bent inwardly, as shown in Fig. 1, and the strips 14 14 rest upon insulation-pieces 16 16 on the spring arms 3 3. The contact-strips 13 13,- 14 14, end 15 15 and the spring-arms 2 2 3 23ers held and supported in proper position by long-screws 17 1 7, which extend transversely bated above t;e' plate. '1 and between the upthrough the plate 1, it being understood that for each set or pair of protectors and coopereting contact-strips onopposite sides of the plate 1 there is a set or pair of holding' screws 17 17. These screws 17 17am insulated-st intervals by insulating-tubes 18, 19, 20, 2 1, 22, and 23;. Between the contacts-1313 and the plate 1v are insulating-strips 24 24, which are properly perforated for the inclosing tubes 19 and 22. Outside. of the contact-- strips 13 13 are insulating-strips 25 25 and metal nuts 26 26'. Outside of the springarms 2 2 are insulating-strips 2-7 27. On the outer side of the right-hand strip 27 is.e switchboard-strip 28, projecting below the same, and on the outer side of the left-hand strip 27 are metallic nuts 29 and 30,thelstter being in contect'with e line-strip 31, whichis interposed between the mete'llicnut 30 and another insulating-strip 32. The .metallic nut 29 is in cdiitect with the spring-arm 3 of. the lelt-hend protector. On the outer side of the switchboard-strip 28 are a metallic nut 33 end an insulating strip 34, and on the outer side of these is an insulating-strip 35. Outside of the spring-arms 3 3-end supporting'the same and the.local contacts 1'4 14 andv 15 15', respectively,'2.re insulating-strips 36 36 36. The nuts for the screws 17 17 are epplied to the outer insulstingstrips 36 36 end suitably tightened, so as to draw and hold the entire structure securely together. The s ring-arm 2 of the left-hand protector and t e spring-arm 3 of the right-hand protector are extended below the insuletingstrips, so as to i orniline and switchboard connectors 37 and 38, respectively. These, together with the line and switchboard connectors 31 and 28, are the connectors to which the Wires of the circuit are connected.

The circuits for the two protectors can be traced as follows: For the right-hand pro tector connection is made from the springsrin 3, to whose lower end a switcizborrdwire is connected to the cap 6, grep te stic': 4, exp 5, suing-arm 2, nietsllic piece 21, l low s01 :w 17, nzetsllic piece 30, and linesee,

connector 31. For the lei't-hand protecttr the circuit is from the switchboerdponneeter 1 2 28 to metallic piece 33, upper screw 17, Inc-J l tallic piece 29, spring e rm. 3, cap 6, graphite e, cap 5-, end spring-arm. 2., to wl'icse lower end 37 connection is mede e line-wire.

A Qgroundeonnectionwith each of the two protectors is provided by s. i'netsllic piece 40, errenghd on too of the piste 1 and. having outwerdlyl projec g 41, located in the rear of tne sp'; 2f .J-ut st a slight distance away iii-7o": dn t, is urrengeinent it is d Y t. the plate 1' is connected with. .nd, sothst the ground-ccntmt 16 bysting upon being connected with the plat-e1 makes the proper ground ccnnectiont The lightningrrester errengerncntis loper ends oil too two protectors constituting each pair. The lightning-errester con .plises two ground-electrodes 4242, de sirebly in the form of carbon plates, and two line-electrodes 43 43, also desirably carbon plates. These two electrodes 43 43 are understood to ,be suitably insulated from the ground-elecupper end 01' the pcs't145 end made in the form of 2. loop, so that its ends are located above the electrodes ,42 42 end 43 43. They ere held out of contact with electrodes 43 43 by small messes 47 47 of readily soi'tensble ll'itr teriel, preferably solder. The ends of the spring 46 tend to become depressed. so that when one or both of the smell messes 4'7 beconze soitened OIILQltBd the ends of spline; 46 again come into-contact with either or both. of the line-electrodes The operetion oi the epperetusuthus con.- structed is as follows: When an undulystrong current passes through one of the. circuits, one or. both of the protective devices which that circuit contains will be'operati-ad. As the operation of both is thessme, that of but one will be described. The undulystrong current causes the graphite. stick of the heat-cartridge of the device which open cteste beccnieso heated esto melt or soften the solder 12, whereupon the lever 8 will be released oruncernented, as it were, by the softening of the solder, thereby allowing-the spring-arm 3 to move outwardly. This in will thereupon proceed to move ly endrwill continue such passes the lower end of the lever .8, and thereby becomes freed from seams such lever and from the heat-cartridge of whlch the lever forms a part. This opens or breaks the circuit by the formation of an opening or gap between the end of the lever 8 and the spring-arm 3, as shown in Fig. 4. The spring-arm 3 comes to rest in an eutward position free and disconnected from its cooperating heat-cartridge, as well shown Fig. 1; but the lever 8 of the heat-cartridge is immediately returned or restored to its orlginal or normal position by the spring 11 cooperating with said lever, This is per mitted because the solder is still in a melted or softened condition, The release of the spring-arm 3, the freeing of the same from the lever 8, and the swinging of the latter back to its original condition, all take place in an exceedingly-short period of time, so

short that the graphite stick and solder do not have time to cool. In a few moments the graphlte 4 and layer of solder 12 will cool sufficiently to allow the solder to become hardened, whereupon-the lever 8 is again held rigldly in position to engage and restrain the spring-arm -3. It is only necessary,

therefore, to place the arm 3 in'engagement with the lever 8 to put the entire protective device'in its normal condition, assuming that only one heat-cartridge has operated. Another unduly-strong current passing the line will a ain heat the graphite 4 of one of the cartri ges to an extent to melt or soften the solder thereof, whereupon the lever 8 will again be swung by the spring 3, so as to cause the release of the latter and the conseguent breakage of the circuit, and immeiately after this the lever 8 will be again restored to its original condition and held there by the hardenin of the solder. Sometimes bothheat cartri ges will operate at the same time on the passage of an excessive current,

in which case both of the levers 8 8 are reset and resoldered preparatory for another operation. In this way the device can be operated time after'time without any replacement or substitution of parts or without manual or machine labor to repair the same.

Whenever one of the heat-cartridges operates and its spring-arm?) is released, the arm 2 also moves inwardly a little and comes into contact with the ground connection 40, thereby grounding one side of the circuit, and the arm 3 swings the contact 14 against contact 15, thereby closing the local circuit, which is understood to be connected in any suitable or usual manner with these contacts 14 and 15. a 1

The lightning-arrester normall remains in the condition shown in Fig. 1. ien, how ever, lightning intrudes upon one of the lines, it escapes from the line-carbon 43 to the spring 46 following the path of least resistthe line-carbon and the spring causes the melting or softening of one of the balls or masses of softenable material 47, whereupon the end of the spring 46 descends upon the line-carbon 43, thereby making connection between the line-carbon and the ground by way of the spring 46. The lightning-arrester is restored to its normal position by inserting a new ball or mass of softenable material 47 between the end of the spring and the ground-carbon 42.

In Figs. 6 and 7 l have shown a modified form of heat-cartridge for use in the form of protector illustrated. In the form shown in a heat-concentrating device instead of the graphite stick 4. This coil of wire 50 is wound upon a suitable core 51, which is desirably an extension of the cap 6. The two ends of the device are connected by an insu lating-cylinder 52, provided with a groove through which the wire of the coil 50 is eX- tended to connect with the ca 5. The cap 6 is provided with a lever 8, soldered in place and with the spring 11-;asbefore.

It will be understood that changes and herein set forth without departing from the spirit of my invention. I

What I claim is- 1. The combination of supporting member 1,. protectors arranged on opposite sides thereof, and each comprising spring-arms 2 and 3 and a heat-responsive device supported at the upper ends of said arms and of an unduly-strong current, a ground con' nection 40, adapted to make contact with the opposite arms 2, 2, a lightning-arrester comprising ground-carbons 42, 42, line-carbons 43, 43, a post 45 having a spring 46, a mass 47 of insulating heat-susceptible material, line lightning-arrester contacts 13, 13, suitable insulating-strips, and screws 17, 17 binding said insulating-strips, spring-arms and consaid support. p

In witness whereof I hereunto subscribe my name this 1st day of February, A. D. 1905. CHARLES A. ROLFE;

, i i itnessesz 1 JAMES D, HAnnIs,

this arcing action across the space between.

these figuresl employ a coil of fine wire 50 asmodifications may be made in the structure adapted to release the same upon the passage.

devices and all mounted at the other side of 

